Yesterday I tried setting the fsck flag on fstab to 2 for the external USB HDD I use in my Raspberry Pi, so that it would be checked on boot, like:
proc /proc proc defaults 0 0 /dev/mmcblk0p5 /boot vfat defaults 0 2 /dev/mmcblk0p6 / ext4 defaults,noatime 0 1 UUID=909274d0-814e-4fe8-b254-4437ec8240c9 /media/pomf288 ext4 defaults,users 0 2
However, today the system failed to boot, reporting this:
/dev/sda2 is mounted.
e2fsck: Cannot continue, aborting.
I understand that obviously the partition is mounted at boot time precisely because it's in the fstab, but so are the root and boot partitions, and both are checked without a problem.
Switching the '2' back to '0' solves the problem, but I would be interested in knowing what can be done about this.